Electronic Tagging

Electronic tagging is a surveillance technique that relies on an electronic device affixed to a person to monitor their location or behaviour. It is widely used in criminal justice settings—typically as a bail or probation condition—but is also found in healthcare, immigration control and various commercial applications. Tagging may use radio frequency systems for short-range monitoring or global positioning system technology when continuous tracking over wider areas is required.

Historical Development

The earliest conceptual foundations for electronic monitoring emerged in the 1960s at Harvard University, where researchers developed a portable transceiver named the behaviour transmitter–reinforcer. Inspired by behaviourist psychology, particularly the work of B. F. Skinner, it enabled two-way communication between a volunteer wearing the device and a fixed base station. Messages were intended to guide the volunteer’s behaviour and encourage rehabilitation. The lead researchers, Ralph Kirkland Schwitzgebel and Robert Schwitzgebel (later Gable), installed the main antenna on a Cambridge church roof.
Initial reactions to the idea were sceptical. Academic reviewers criticised the potential for intrusive supervision, and popular accounts mischaracterised the device as involving implants or audio instruction. Attempts to commercialise the system failed, and wider penal shifts in the United States during the 1970s—moving away from rehabilitative sentencing—meant that the technology did not progress.
Interest revived in the early 1980s. In 1982, Arizona judge Jack Love worked with Michael T. Goss to establish National Incarceration Monitor and Control Services, producing an electronic ankle transmitter roughly the size of a credit card. The device emitted regular radio signals to a nearby receiver connected to a telephone line, allowing breaches of home detention to be reported. The first trial in 1983 covered three probationers; although home curfews were monitored successfully, two of the individuals reoffended. Nonetheless, the approach gained traction as computing and communication technologies advanced.
A collection of early monitoring equipment is preserved at the National Museum of Psychology in Akron, Ohio.

Technological Developments

Modern systems adopt multiple technologies to enhance monitoring:

• Radio-frequency ankle tags for proximity-based checks, typically confirming whether an individual is at home during curfew hours.
• GPS-enabled tags, allowing continuous location tracking across wider geographical areas.
• Communication links through landlines, mobile networks or secure digital channels.
• Automated alerts that signal breaches such as curfew violations or tampering.

Specialised devices include sweat-monitoring alcohol tags such as the Secure Continuous Remote Alcohol Monitoring system, which measures perspiration every 30 minutes to detect alcohol use. Similar systems were introduced in England and Wales in 2021 for offenders convicted of alcohol-related crimes.

Uses Beyond the Criminal Justice System

Electronic tagging has expanded into non-judicial contexts:

• Medical and health settings: Tagging supports safety for elderly individuals or those with dementia by preventing wandering and facilitating rapid location. This application has prompted debate surrounding patient autonomy, safety and privacy.
• Commercial and consumer uses: Smartphones routinely integrate GPS functions for navigation and tracking.
• Parental monitoring: GPS-enabled uniforms and backpacks in Japan allow children in distress to alert security services.
• Public transport: GPS-based monitoring of vehicles enables accurate arrival information for passengers.

Effectiveness and Implementation

Research suggests that electronic monitoring can support compliance with legal conditions and may deter reoffending when implemented appropriately. Factors influencing effectiveness include:

• Well-defined selection of individuals for monitoring.
• Reliable hardware and communication systems.
• Rapid responses to alerts and breaches.
• Effective cooperation between supervisory agencies and technology providers.